TrajectView now draws an arrow at each endpoint (since pieces oscillate
between start and end, both directions are relevant) and runs a looped
width/alpha tween that breathes between 0.3 and 0.75 over ~2.2s. The
pulse makes stationary relays visually distinct from static board art
without competing with active cargo/particle animations.
Black box sim engine (commands in, events out) with 3 piece types
(Rook, Bishop, Knight), cargo transfer system with social status
priority, collision detection, and victory/defeat conditions.
57 tests covering rules, simulation, loading, and solvability.
Godot 4 presentation layer scaffolding.